How Scientology controls John Travolta and Tom Cruise, according to 'Going Clear'

HBO hired 160 lawyers when the network decided to air Going Clear: Scientology and the Prison of Belief, the two-hour documentary based on Lawrence Wright's book. This makes sense when you watch the film, directed by Alex Gibney, which aired Sunday night. Ex-Church of Scientology members and officials reveal secrets of the organisation, and tell horror stories of psychological and physical abuse during their time in the controversial religion — and after they escaped. (For the record, the church unleashed a series of attack ads against the film and says that it's "bigoted propaganda" and " built on falsehoods invented by admitted liars.")

One particularly fascinating subject that the documentary tackles is the relationship between celebrities and the church, which has been well-documented particularly with two of its most famous members: John Travolta and Tom Cruise. The film goes into detail about how much Scientology leader David Miscavige relies on star power to recruit new members and raise money.

The Church of Scientology — worth billions of dollars — is considered tax-exempt by the Internal Revenue Service, which waged a nasty battle with the church for years before giving up and declaring it a non-profit religious organisation in 1993. As Wright says in Going Clear, there are only two ways to stop the church. One: The IRS could change its mind and start looking into finances. The other? "Some of these celebrity megaphones could turn against the church," says Wright. "And Tom Cruise should be leading that chorus."